*4.11. Sample Extraction for Total Anthocyanin Content and Total Phenolic Content*

Before analyzing the TAC and TPC of fresh-cut purple sweet potatoes, the sample pieces were frozen (−80 ◦C) and freeze-dried (FDS8518, Ilsin BioBase Co. Ltd., Dongducheon-si, Republic of Korea) for 7 days. Finally, the freeze-dried samples were ground, and their powder was stored in a freezer at −20 ◦C using extraction. 0.5 g of dried powder was weighed into a centrifuge tube and dissolved in 10 mL of 50% ethanol. Next, the sample solutions were homogenized for 30 min using an ultrasonic cleaner (JAC-3010; KODO, Hwaseong, Republic of Korea). The tube was placed in a centrifuge (45,000 rpm for 15 min), and finally, clear supernatant was obtained after filtration.
